U.S. patent application number 10/811565 was filed with the patent office on 2005-10-13 for controlled separation heart valve frame.
Invention is credited to Marquez, Salvador.
Application Number | 20050228494 10/811565 |
Document ID | / |
Family ID | 34963901 |
Filed Date | 2005-10-13 |
United States Patent
Application |
20050228494 |
Kind Code |
A1 |
Marquez, Salvador |
October 13, 2005 |
Controlled separation heart valve frame
Abstract
A highly flexible prosthetic heart valve having an internal
leaflet support frame that is designed to separate into individual
cusps after implantation. The leaflet support frame (or "stent" or
"wireform") has a plurality of alternating cusps on an inflow end
and commissures on an outflow end. The cusps of flexible leaflets
attach around the support frame cusps. The support frame provides
structural rigidity during implantation, but each support frame
commissure has a point of weakness that is designed to fracture
upon repeated relative movement of the cusps after implantation
such that the support frame cusps separate. Because of the flexible
nature of the heart valve, after the cusps separate the implanted
heart valve does not significantly impede the natural motions of
the annulus or adjacent vessel walls. The support frame may be a
homogeneous material such as Nitinol with the point of weakness
being a narrowing at the commissure tips. The commissure tips can
include enlarged regions adjacent the point of weakness that help
prevent the separated ends from poking through surrounding
fabric.
Inventors: |
Marquez, Salvador; (Foothill
Ranch, CA) |
Correspondence
Address: |
EDWARDS LIFESCIENCES CORPORATION
LEGAL DEPARTMENT
ONE EDWARDS WAY
IRVINE
CA
92614
US
|
Family ID: |
34963901 |
Appl. No.: |
10/811565 |
Filed: |
March 29, 2004 |
Current U.S.
Class: |
623/2.18 ;
623/2.38 |
Current CPC
Class: |
A61F 2/2418 20130101;
A61F 2220/0066 20130101 |
Class at
Publication: |
623/002.18 ;
623/002.38 |
International
Class: |
A61F 002/24 |
Claims
What is claimed is:
1. A support frame for a flexible leaflet prosthetic heart valve,
comprising: a plurality of cusps each sized and shaped to support a
cusp of a flexible leaflet of the heart valve; and a plurality of
commissures, one each between each adjacent pair of cusps, the
commissures each having a point of weakness designed to fracture
upon repeated relative movement of the cusps after implantation
such that the cusps move substantially independently of each
other.
2. The support frame of claim 1, wherein the support frame is a
single, continuous, element.
3. The support frame of claim 2, wherein the support frame is
formed from a continuous, homogeneous material.
4. The support frame of claim 3, wherein the commissures and cusps
have substantially the same material stiffness in bending prior to
reaching the point of fatigue.
5. The support frame of claim 1, wherein the support frame is made
of Nitinol.
6. The support frame of claim 1, wherein each cusp of the support
frame transitions into two commissure regions, and wherein the
point of weakness at the commissures comprises a frangible bridge
between adjacent commissure regions.
7. The support frame of claim 6, wherein the frangible bridge
comprises a narrow portion of the support frame relative to
adjacent portions.
8. The support frame of claim 6, wherein the point of weakness
comprises a notch.
9. The support frame of claim 6, wherein the commissure regions
terminate in enlarged ears on either side of the frangible
bridge.
10. The support frame of claim 9, further including a biocompatible
fabric covering the support frame, and wherein the enlarged ears
are sized to prevent the commissure regions from poking through the
fabric once the frangible bridge has fractured.
11. A support frame for a flexible leaflet prosthetic heart valve,
comprising: a plurality of cusps sized and shaped to support cusps
of flexible leaflets of the heart valve; and a plurality of
commissures, one each between each adjacent pair of cusps, the
commissures and cusps being formed integrally of a homogeneous
material and the commissures each having a point of weakness
designed to fracture upon repeated relative movement of the cusps
after implantation whereby the cusps can move substantially
independently of each other.
12. The support frame of claim 11, wherein the support frame
coprises three cusps and three commissures.
13. The support frame of claim 11, wherein the support frame is
made of Nitinol.
14. The support frame of claim 11, wherein each cusp transitions
into two commissure regions, and wherein the point of weakness at
the commissures comprises a frangible bridge between adjacent
commissure regions.
15. The support frame of claim 14, wherein the frangible bridge
comprises a narrow portion of the support frame relative to
adjacent portions.
16. The support frame of claim 14, wherein the point of weakness
comprises a notch.
17. The support frame of claim 14, wherein the commissure regions
terminate in enlarged ears on either side of the frangible
bridge.
18. The support frame of claim 17, further including a
biocompatible fabric covering the support frame, and wherein the
enlarged ears are sized to prevent the commissure regions from
poking through the fabric once the frangible bridge has
fractured.
19. A method of replacement of a natural heart valve with a
flexible leaflet prosthetic heart valve, comprising: providing a
flexible leaflet prosthetic heart valve having an internal support
frame with alternating cusps and commissures, the cusps of the
flexible leaflets being attached along the support frame cusps, the
commissures of the internal support frame being designed to
fracture upon repeated relative movement of the cusps after
implantation such that the support frame cusps move substantially
independently of each other; and implanting the flexible leaflet
prosthetic heart valve.
20. The method of claim 19, wherein the internal support frame is
made of a continuous flexible element which will withstand and
spring back from substantial compressive forces imparted thereon
during the implanting step.
21. The method of claim 19, wherein the step of implanting the
flexible leaflet prosthetic heart valve comprises compressing the
valve and delivering it to the site of implantation through a tube
in a less-invasive procedure.
22. The method of claim 19, wherein the flexible leaflet prosthetic
heart valve is designed to be implanted in the aortic position and
further includes a sewing band that follows the alternating cusps
and commissures of the support frame, and wherein the step of
implanting comprises attaching the sewing band up and down the
fibrous cusps and commissures of the natural aortic annulus and
ascending aorta.
23. The method of claim 19, wherein the commissures of the internal
support frame are designed to fracture from between about two days
and two weeks after implantation.
Description
FIELD OF THE INVENTION
[0001] The present invention pertains to an internal support frame
for a prosthetic heart valve and, more particularly, to a leaflet
support frame that separates into cusps after implantation.
BACKGROUND OF THE INVENTION
[0002] Prosthetic heart valves are used to replace damaged or
diseased heart valves. In vertebrate animals, the heart is a hollow
muscular organ having four pumping chambers: the left and right
atria and the left and right ventricles, each provided with its own
one-way outflow valve. The natural heart valves are identified as
the aortic, mitral (or bicuspid), tricuspid and pulmonary valves.
The valves of the heart separate chambers therein, and are each
mounted in an annulus therebetween. The annuluses comprise dense
fibrous rings attached either directly or indirectly to the atrial
and ventricular muscle fibers. In a valve replacement operation,
the damaged leaflets are typically excised and the annulus sculpted
to receive a replacement valve.
[0003] The four valves separate each ventricle from its associated
atrium, or from the ascending aorta (left ventricle) or pulmonary
artery (right ventricle). After the leaflets have been excised, the
annulus generally comprises a ledge extending into and defining the
orifice between the respective chambers. Prosthetic valves may
attach on the upstream or downstream sides of the annulus ledge,
but preferably reside outside of the ventricles to avoid
interfering with the large contractions therein. Thus, for example,
in the left ventricle a prosthetic valve is preferably positioned
on the inflow side of the mitral valve annulus (toward the left
atrium), or on the outflow side of the aortic valve annulus (toward
the ascending aorta).
[0004] One of the primary types of heart valve prostheses is a
tissue-type or "bioprosthetic" valve which is constructed with
natural-tissue valve leaflets (whole valve, e.g., porcine, or a
plurality of leaflets, e.g., from bovine equine or other
pericardium) which function much like a natural human heart valve,
imitating the natural action of the flexible heart valve leaflets
which seal against each other to ensure the one-way blood flow.
Synthetic leaflets have also been proposed, and thus the term
"flexible leaflet valve" refers to both natural and artificial
"tissue-type" valves. Two or more flexible leaflets are mounted
within a peripheral support structure that usually includes posts
or commissures extending in the outflow direction to mimic natural
fibrous commissures in the native annulus. Components of the valve
are usually assembled with one or more biocompatible fabric (e.g.,
Dacron) coverings, and a fabric-covered sewing ring is typically
provided on the inflow end of the peripheral support structure.
[0005] In most bioprosthetic-type valves, a metallic or polymeric
structure provides base support for the flexible leaflets, which
extend therefrom. One such support is an elastic "support frame,"
sometimes called a "wireform" or "stent," which has a plurality
(typically three) of large radius cusps supporting the cusp regions
of each flexible leaflet. The ends of each pair of adjacent cusps
converge somewhat asymptotically to form upstanding commissures
that terminate in tips, each extending in the opposite direction as
the arcuate cusps and having a relatively smaller radius. The
support frame typically describes a conical tube with the
commissure tips at the small diameter end. This provides an
undulating reference shape around which a fixed edge of each
leaflet attaches (via components such as fabric and sutures) much
like the natural fibrous skeleton in the aortic annulus. One
example of the construction of a flexible leaflet valve is seen in
U.S. Pat. No. 5,928,281 to Huynh, et al. (Edwards Lifesciences,
Corp., Irvine, Calif.), in which the exploded view of FIG. 1
illustrates a fabric-covered wireform 54 and a fabric-covered
support stent 56 on either side of a leaflet subassembly 52.
[0006] Because of the rigidity of the material used in the support
frame, conventional valves have a diameter that is minimally
affected by the natural motion of the heart orifice. In the aortic
position, the commissures extend in the downstream direction a
spaced distance from the walls of the downstream aortic wall.
Movement of the aortic wall or sinuses does not substantially
affect movement of the cantilevered commissures, though fluid flow
and pressures generated by movement of the walls ultimately does
cause the commissures to dynamically flex to some extent (i.e.,
they are cantilevered downstream in the aorta). Natural dilatation
of the annulus is therefore restricted, imposing an artificial
narrowing of the orifice, and increasing the pressure drop
therethrough.
[0007] Some flexible leaflet prosthetic heart valves are designed
to be relatively more flexible. For example, U.S. Pat. No.
4,106,129 to Carpentier, et al. discloses a heart valve with a
compliant supporting stent capable of annular deformation. The
stent is made with a single flexible wire pre-formed to define
inverted U-shaped commissures supports merging smoothly with
connecting arcuate portions. The heart valve in Carpentier, et al.
is capable of yielding to a limited extent in response to forces
which tend to alter the configuration and circumference of the
supporting stent. FIGS. 9 and 10 of the '129 patent illustrate
aortic and mitral embodiments, respectively, with sewing rings
adapted to attach to the particular annulus.
[0008] More recently, U.S. Pat. No. 6,558,418 to Carpentier, et al.
discloses a highly flexible tissue-type heart valve having a
structural stent in a generally cylindrical configuration with
cusps and commissures that are permitted to move radially. The
stent commissures are constructed so that the cusps are pivotably
or flexibly coupled together at the commissures to permit relative
movement therebetween. The prosthetic valve of the '418 patent is
designed such that alternating peripheral portions are attached to
the aortic annular region and the sinus region, and the flexible
valve accommodates the in-and-out movements of both regions. The
structural stent is useful during implantation to maintain the
valve shape for proper suturing, and to provide a barrier to
leaflet placations. However, once implanted, the structural stent
still provides an impediment to complete flexibility.
[0009] Accordingly, there is a need for a highly flexible heart
valve that responds to and does not significantly impede the
natural motions of the annulus and adjacent vessel walls but which
also maintains a desired shape during implantation
SUMMARY OF THE INVENTION
[0010] The present invention provides an improved leaflet support
frame for a prosthetic heart valve that maintains its shape during
implantation but eventually separates into a plurality of cusps
thereafter. The support frame includes alternating cusps and
commissures with a plurality of flexible leaflets secured along
their cusp edges to the frame, one per frame cusp. The frame
commissures are designed to fracture at a period after implantation
such that the cusps move substantially independently of each other.
In contrast to earlier biodegradable cusp connections, the frame
commissures have substantially the same material stiffness in
bending as the frame cusps so as to substantially limit the
possibility of the valve cusps prematurely breaking free of each
other from the inevitable manipulation of the valve during
implantation.
[0011] In accordance with one embodiment, a support frame for a
flexible leaflet prosthetic heart valve is provided that has a
plurality of cusps each sized and shaped to support a cusp of a
flexible leaflet of the heart valve, and a plurality of
commissures, one between each adjacent pair of cusps. The
commissures and cusps have substantially the same material
stiffness in bending, but the commissures each have a point of
weakness designed to fracture upon repeated relative movement of
the cusps after implantation thereby permitting the cusps to move
substantially independently of each other.
[0012] In an alternative embodiment, the support frame comprises a
plurality of cusps sized and shaped to support cusps of flexible
leaflets of the heart valve, and a plurality of commissures, one
between each adjacent pair of cusps. The commissures and cusps are
formed integrally of a homogeneous material and the commissures
each have a point of weakness designed to fracture upon repeated
relative movement of the cusps after implantation thereby
permitting the cusps to move substantially independently of each
other. Preferably, the support frame is made of a flexible material
such as Nitinol.
[0013] Preferably, each cusp of the support frame transitions into
two commissure regions, and wherein the point of weakness at the
commissures comprises a frangible bridge between adjacent
commissure regions. The frangible bridge may comprise a narrow
portion of the support frame relative to adjacent portions, or may
be a notch. Desirably, the commissure regions terminate in enlarged
ears on either side of the frangible bridge. The support frame may
be covered with a biocompatible fabric, and the enlarged ears are
sized to prevent the commissure regions from poking through the
fabric once the frangible bridge has fractured.
[0014] The invention also encompasses a method of replacement of a
natural heart valve with a flexible leaflet prosthetic heart valve.
The method includes providing a flexible leaflet prosthetic heart
valve having an internal support frame with alternating cusps and
commissures, the cusps of the flexible leaflets being attached
along the support frame cusps. The commissures of the internal
support frame are designed to fracture upon repeated relative
movement of the cusps after implantation such that the support
frame cusps can move substantially independently of each other. The
method includes implanting the flexible leaflet prosthetic heart
valve.
[0015] Desirably, the internal support frame is made of a
continuous flexible element which will withstand and spring back
from substantial compressive forces imparted thereon during
implantation. The step of implanting the flexible leaflet
prosthetic heart valve may comprise compressing the valve and
delivering it to the site of implantation through a tube in a
less-invasive procedure. In one version, the flexible leaflet
prosthetic heart valve is designed to be implanted in the aortic
position and further includes a sewing band that follows the
alternating cusps and commissures of the support frame. The step of
implanting the heart valve therefore comprises attaching the sewing
band up and down the fibrous cusps and commissures of the natural
aortic annulus and ascending aorta. In accordance with an exemplary
embodiment, the commissures of the internal support frame are
designed to fracture from between approximately two days and two
weeks after implantation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is an exploded view of components of a prosthetic
heart valve of the present invention;
[0017] FIG. 2 is a perspective view of an exemplary leaflet support
frame of the present invention seen from an outflow end;
[0018] FIG. 2A is an enlarged view of one of the commissure tips of
the leaflet support frame of FIG. 2; and
[0019] FIG. 3 is a perspective view of the leaflet support frame
seen from an inflow end.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] The present invention provides a highly flexible prosthetic
heart valve that is primarily suited for implantation in the aortic
position. In particular, the prosthetic heart valve has an
attachment or sewing band that follows the undulating shape of an
internal support frame. As such, the sewing band may be attached
(e.g., with sutures) up and down the fibrous cusps and commissures
of the natural aortic annulus and ascending aorta. It should be
understood, however, that the characteristics of the heart valve of
the present invention may also be suitable for use in other valve
locations, such as in the tricuspid position.
[0021] The prosthetic heart valve is highly flexible and includes
an internal frame that supports a plurality of flexible leaflets
providing occluding surfaces for the valve. The internal frame is
designed to break apart into separate cusps, one per leaflet, after
implantation to render the valve even more flexible. One example of
construction of a prosthetic heart valve is shown and described
below, although it should be understood that the invention is not
limited by a particular valve construction. Any valve that has
flexible leaflets supported around their periphery may include an
internal frame that separates into parts after implantation. A
particular preferred construction of a flexible heart valve, aside
from substitution of the separable internal support frame described
herein, is disclosed in U.S. Pat. No. 6,558,418 to Carpentier, et
al., which is expressly incorporated herein by reference.
[0022] As mentioned above, the term "flexible leaflet" refers to
any valve leaflet that flexes and "coapts" against the other
leaflets to close the valve, much like the native leaflets. Because
of the separable internal support frame and relative cusp
movements, at least the coapting edges of the leaflets must be
somewhat flexible to accommodate the motion of the peripheral
support structure. Preferably, the flexible leaflets are separate
synthetic (e.g., polymer) or natural (e.g., pericardium) leaflets
attached to the peripheral support structure. However, whole
natural valves such as xenograft porcine valves may be used. Also,
it is conceivable that a synthetic leaflet that is partly rigid but
flexible along its coapting edge may be used.
[0023] FIG. 1 illustrates in exploded view primary components of an
exemplary prosthetic heart valve 20 of the present invention. The
heart valve 20 includes a subassembly of flexible leaflets 22,
preferably comprising three separate leaflets 24a, 24b, 24c. Each
leaflet includes an arcuate cusp edge 26 on an inflow end opposite
a free or coapting edge 28 on an outflow end. In the exemplary
embodiment, a pair of tabs 30 extend outward from either end of the
coapting edge 28. As explained in U.S. Pat. No. 6,558,418, such
tabs can be used to secure the leaflets 24 to commissures of a
peripheral support frame in a manner that reduces stress in the
attachment sutures. Each tab on the leaflets is juxtaposed against
a tab on an adjacent leaflet so that there are three pairs of
contacting tabs extending outward approximately 120 degrees apart
in the leaflet subassembly 22.
[0024] The leaflet subassembly 22 (or separate leaflets 24) is held
in place within the valve 20 by a support structure comprising a
cloth-covered support frame 40 and a sewing band 42. The sewing
band 42 is also desirably covered with cloth or some other material
that aids connectivity and/or biocompatibility. The support frame
40 and sewing band 42 are similarly shaped with a plurality,
preferably three, posts or commissures extending in an outflow
direction and a plurality of arcuate cusps on an inflow end. As can
be seen from FIG. 1, the arcuate cusps of the support structure
correspond to be leaflet cusps 26.
[0025] The exemplary leaflet support frame 40 (shown without its
cloth cover in FIGS. 2 and 3) includes three upstanding commissures
44a, 44b, 44c terminating in tips 46a, 46b, 46c, and three arcuate
cusps 48a, 48b, 48c. Although not clearly shown, the surface of
revolution defined by the leaflet support frame 40 is desirably a
cylinder or more preferably, a cone, with the commissure tips 46
being disposed slightly radially closer together than the apices of
the arcuate cusps 48. A cloth cover seen in FIG. 1 closely
surrounds the support frame 40 and preferably provides an outwardly
extending flap 50 that is used to secure the valve components
together. The material of the cloth cover may be any biocompatible
fabric, preferably a polymer fabric such as polyethylene
terepthalate (PET). Greater details of the leaflet support frame
40, a primary subject of this invention, are provided below.
[0026] The sewing band 42 also has three upstanding commissures
54a, 54b, 54c terminating in tips 56a, 56b, 56c, and three arcuate
cusps 58a, 58b, 58c. A variety of suture-permeable materials may be
used, although a molded silicone core covered with a fabric (e.g.,
PET) is preferred.
[0027] When assembled, the leaflets 24 are sandwiched between and
attached to both the support frame 40 and sewing band 42. Sutures
are typically used to join the outwardly projecting flap 50 of the
support frame 40 through the cusp edges 26 of the leaflets 24 and
through the cloth-covered sewing band 42. Although not shown, each
pair of leaflet tabs 30 projects outward through gaps 60 in the
support frame 40 and may be folded away from one another so as to
lie to the inside of each of the commissures 54 of the sewing band
42 in the assembled valve 20. Again, although various construction
details may be modified, each leaflet 24 is desirably generally
continuously attached around the support frame 40 along the cusp
edge 26 and at the two tabs 30. The coapting edge 28 remains
free.
[0028] Now with reference to FIGS. 2 and 3, the support frame 40
may be fabricated as a single, continuous, integral, wire-like
element 70 of a homogeneous material. One particularly desirable
material is Nitinol, and a preferred fabrication technique is to
laser-cut a 2-dimensional blank from a sheet, or a 3-dimensional
blank from a tube, and then bend and heat treat the blank into the
illustrated shape. Further details on this technique can be seen in
U.S. patent application Ser. No. 10/423,019, filed Apr. 24, 2003,
the disclosure of which is expressly incorporated herein by
reference. Using such techniques, the cross-section of the element
70 will typically be square or rectilinear, although
electro-polishing is desirably performed to microscopically round
the corners.
[0029] Nitinol is preferred because of its biocompatibility
combined with flexible qualities. That is, the support frame 40
must be relatively stiff to maintain the valve shape during
implantation when the surgeon is attempting to manipulate and
attach the valve into place. At the same time, the support frame 40
should be capable of springing back from the sometimes strong
forces experienced during the implantation procedure.
Alternatively, the support frame 40 may be made of a single,
continuous piece of an alloy of carbon, silicon, phosphorus,
sulphur, chromium, nickel, beryllium, cobalt, iron, manganese and
molybdenum which is sold under the ELGILOY trade name by Elgiloy,
L.P. of Elgin, Ill., U.S.A. Another potentially useful material is
titanium or an alloy thereof. The support frame 40 could also be
molded from a polymer, such as DELRIN, or any other biocompatible
material exhibiting appropriate flexibility.
[0030] FIG. 2A is an enlargement of one of the commissure tips 46.
In a preferred embodiment, the cross-section of the wire-like
element 70 is substantially constant around the entire support
frame 40 except at the tips 46. Each arcuate cusp 48a, 48b, 48c
transitions into a commissure region 72 adjacent to the tips 46.
The commissure regions are generally linear and extend upward to an
enlarged ear 74. Adjacent ears 74 join across a relatively weak
point or frangible bridge 76 at the center line of the commissure
tip 46. The frangible bridge 76 comprises a narrowing of the
cross-section of the elongated element 70 relative to the rest of
the element. The bridge 76 is designed to fatigue and fracture
after the valve is implanted so that the cusps 48 separate, or in
other words, become free to move substantially independently of
each other (though they will preferably remain coupled via the
sewing band 42 or surrounding fabric).
[0031] For a support frame 40 fabricated as a continuous Nitinol
element, the bridge 76 desirably has a cross-section of
approximately 0.015" (0.381 mm) in height (axial dimension) and
0.020" (0.508 mm) thickness (radial dimension). Although the length
of the bridge 76 does impact the moment arm from the ears 74, and
thus any stress applied thereto after implantation the length is
relatively small (approximately the same as the height) and small
changes will not greatly alter the stress. With this cross-section,
the bridge 76 is designed to fatigue and fracture anywhere between
about 2 days and 2 weeks after implantation (or equivalent number
of cycles at a heart beat rate 1 Hz). Those of skill in the art
will understand that depending on the material/construction and
desired time to fracture, the specific dimensions of the bridge 76
may vary. In the illustrated embodiment, the frangible bridge 76
comprises a narrow length of material between the ears 72, but
another technique is to provide a notch or other such feature that
creates a stress point in the bridge.
[0032] An alternative construction process is to form three
separate cusps and to connect them at the frangible bridges 76. To
provide the benefits of the invention the connection should have a
stiffness/rigidity similar to a bridge formed integrally with the
cusps 48. That is, the commissure tips 46a, 46b, 46c should be
relatively rigid at implant to prevent the arcuate cusps 48a, 48b,
48c from unduly pivoting with respect to one another. Of course,
some cusp pivoting may occur due to the inherent flexibility of the
support frame 40, just as long as the commissure tips 46a, 46b, 46c
unduly do not increase that flexibility. For example, a welded
connection between adjacent ears 74 might be designed to break some
time after implantation. Alternatively, a separate member forming
the bridge 76 might be connected at each end to the surrounding
ears 74 by welding or threading, for example. It should be clear
that there are various ways to fabricate a support frame 40 that
has commissures and cusps with substantially the same material
stiffness in bending but a point of weakness at each commissure
designed to fracture upon repeated relative movement of the cusps
after implantation such that the cusps separate.
[0033] In another aspect of the invention, the enlarged ears 74
help prevent the separated cusps 48 of the support frame 40 from
poking through the surrounding fabric. In a preferred embodiment,
the enlarged ears 74 desirably have a radius of about 0.5-1.5 mm,
preferably about 1.0 mm, to prevent fabric poke-through.
[0034] The present heart valve is used in a surgical method of
replacing a natural heart valve. Any of the aforementioned heart
valves are implanted in the appropriate location (e.g., in the
aortic annulus and ascending aorta) using traditional open-chest
surgery, or a less-invasive surgery such as a mini-thoracotomy, or
even percutaneously. If the support frame 40 of the heart valve is
made of a highly flexible material such as Nitinol, the valve may
be compressed to a relatively small package and inserted using a
minimally-invasive technique, such as percutaneously through a
catheter passed up through the femoral artery. Another technique
that may be used is through a port access incision in the chest.
One particularly advantageous aspect of the invention is that the
support frame allows for the bending of the frame at the commissure
tips during implantation, but because it is a continuous or at
least unitary piece, does not allow for relative axial motion of
the commissures.
[0035] Once in position, the surgeon secures the valve to the
surrounding anatomy using sutures, staples, or other such
attachment structures as are known in the field. Depending on the
technique used, the attachment structure may be manipulated
manually, or via robotic assistance.
[0036] It will also be appreciated by those of skill in the
relevant art that various modifications or changes may be made to
the examples and embodiments described without departing from the
intended scope of the invention. In this regard, the particular
embodiments of the invention described herein are to be understood
as examples of the broader inventive concept disclosed.
* * * * *